Add tests for RegisterBuildService how builds are picked when they have a quota set

spec/services/ci/register_build_service_spec.rb

@@ -130,6 +130,62 @@ module Ci
         end
       end
 
+      context 'for project with shared runners when global minutes limit is set' do
+        before do
+          project.update(shared_runners_enabled: true)
+          stub_application_setting(shared_runners_minutes: 500)
+        end
+
+        context 'allow to pick builds' do
+          let(:build) { execute(shared_runner) }
+
+          it { expect(build).to be_kind_of(Build) }
+        end
+
+        context 'when over the global quota' do
+          before do
+            project.namespace.create_namespace_metrics(
+              shared_runners_minutes: 600)
+          end
+
+          let(:build) { execute(shared_runner) }
+
+          it "does not return a build" do
+            expect(build).to be_nil
+          end
+
+          context 'when project is public' do
+            before do
+              project.update(visibility_level: Project::PUBLIC)
+            end
+
+            it "does return the build" do
+              expect(build).to be_kind_of(Build)
+            end
+          end
+
+          context 'when namespace limit is set to unlimited' do
+            before do
+              project.namespace.update(shared_runners_minutes_limit: 0)
+            end
+
+            it "does return the build" do
+              expect(build).to be_kind_of(Build)
+            end
+          end
+
+          context 'when namespace quota is bigger than a global one' do
+            before do
+              project.namespace.update(shared_runners_minutes_limit: 1000)
+            end
+
+            it "does return the build" do
+              expect(build).to be_kind_of(Build)
+            end
+          end
+        end
+      end
+
       context 'disallow shared runners' do
         before do
           project.update(shared_runners_enabled: false)